Visible-telecom tunable dual-band optical isolator based on dynamic modulation in thin-film lithium niobate.

Optical isolators are an essential component of photonic systems. Current integrated optical isolators have limited bandwidths due to stringent phase-matching conditions, resonant structures, or material absorption. Here, we demonstrate a wideband integrated optical isolator in thin-film lithium niobate photonics. We use dynamic standing-wave modulation in a tandem configuration to break Lorentz reciprocity and achieve isolation. We measure an isolation ratio of 15 dB and insertion loss below 0.5 dB for a continuous wave laser input at 1550 nm. In addition, we experimentally show that this isolator can simultaneously operate at visible and telecom wavelengths with comparable performance. Isolation bandwidths up to ∼100 nm can be achieved simultaneously at both visible and telecom wavelengths, limited only by the modulation bandwidth. Our device's dual-band isolation, high flexibility, and real-time tunability can enable novel non-reciprocal functionality on integrated photonic platforms.